Denny’s ran email on Mailchimp and SMS on a separate platform. The two channels lived in different systems, with fragmented subscriber data, limited automation, and no single view of the customer. Roswell recommended that Denny’s consolidate everything onto Klaviyo, rebuild the automation program from the ground up, and add SMS, all without losing deliverability or revenue during the move.

In its first seven months on Klaviyo (November 2025 through May 2026), email and SMS together drove approximately 28 percent of total store revenue, with email-attributed revenue growing nearly tenfold (9.7x) from the program's first full month on the platform to May.

Automated flows account for about a quarter of email-and-SMS revenue, led by cart abandonment at 25 percent of flow revenue, abandoned checkout at 16 percent, post-purchase at 14 percent, and the welcome series at 12 percent.

Denny's added roughly 13,800 net-new email subscribers since the migration, unique monthly email clickers grew more than tenfold from November to May, and returning customers account for about 76 percent of all orders — all while the store grew approximately 14 percent year over year.

Consolidating onto Klaviyo gave Denny’s one source of truth and a retention program that compounds month over month. In seven months it went from a migration project to roughly a quarter of store revenue, with SMS still early and seasonal flows continuing to ramp. One platform, two channels, and a growing share of revenue that Denny’s owns outright.